I have called around and compared prices even as far as 30 miles away. So we got the best price in the area, and it is with the vet that we normally use.
Look at the individuals that have grade stallions with grade mares and are selling them, or have a whole mix of stallions. That is kind of where the problem is at. No matter if it is $75 or $500, somewhere people are saying, 'Cannot afford that'. I am not trying to single anyone out or state that a grade horse is no good. The best mare at the barn is a shetland / quarter cross.
It is just a concern for others. We were concerned about the little stud that was at the barn and that is why we got together to get him fixed. Although he was kept in a pretty nice area with 7ft call welded / panel fence. Soon he will be able to run with the girls and no worries on everyone's mind.
Some rescues are working on getting low cost gelding programs set up - much like the clinics they do for cats and dogs. Some vet schools alraedy offer them. There were a few that were doing $50 geldings. Specifically for the reasons you stated above.